62 



THE ACTINOMYCETES, Vol. I 



Figure 30. The genus Actinoplanes 



species was described, but not named, by 

 Nocard. Trevisan regarded it as the type 

 species of the new genus. N . actinomyces 

 Trevisan (Syn. Actinomijces hovis Harz) 

 was given as the second species. This was 

 followed by A^. foersteri (Cohn) Trevisan 

 (Syn. Streptothrix foersteri Cohn). In con- 

 sidering these facts. Breed and Conn con- 

 cluded that "There appears to be no justifi- 

 cation for the use of the term Nocardia 

 Trevisan for the entire group of organisms 

 included in the Actinomycetaceae. It may, 

 however, he properly used for a subdivision 

 of the genus Actinomijces, provided, how- 

 ever, N . farcinica is retained in the genus 

 Nocardia and is established as the type of 

 the genus." 



Waksman and Henrici further considered 

 the need of a valid name for the aerobic 

 sporulating species. They concluded that 

 the only solution for this problem was to 

 coin a new generic name, and proposed 

 Streptomyces, a word derived from the first 

 two names given to the actinomycetes as a 

 whole (Strepto-thrix and Actino-rtiyces). 

 Since the Botanical Code recommended that 

 family names be derived from generic names, 

 the new family name Streptomycctaceac was 

 proposed for the spore-forming actinomy- 

 cetes. 



Streptoynycetaeeae included actinomycetes 

 with branched, slender substrate mycelium. 



nonseptate or rarely septate, forming spores 

 on aerial hyphae, and not fragmenting into 

 oidia. Two genera were included in this 

 family: Streptomyces and Micromonospora. 

 Spores are npparently endogenous in origin, 

 formed by a segregation of protoplasm 

 within the hypha into a series of round, oval, 

 or cylindric bodies. Chains of spores are 

 often spirally coiled. Sporophores may be 

 simple or branched. 



Waksman and Henrici selected as the 

 type species of this newly named genus, 

 Streptomyces albus (Rossi-Doria emend Krain- 

 sky) comb. nov. This species was first 

 described as Streptothrix alba Rossi-Doria 

 and later known as Actinomyces albus 

 Krainsky. This is one of the commonest and 

 best known species of the genus, and though 

 it may now be recognized as a group and be 

 subdivided into several species, it was con- 

 sidered, for the time being, as definite a 

 species as any others. It produces colorless 

 vegetative growth, with white aerial myce- 

 lium, and forms ovoidal spores in coiled 

 chains on lateral branches of the aerial 

 hyphae. It is proteolytic, licjuefying gelatin 

 and peptonizing milk with the production 

 of an alkaline reaction in the latter. It does 

 not produce any soluble pigment either on 

 organic or synthetic media, and forms a 

 characteristic earthy or musty odor, as de- 

 scribed in detail later. 



The generic name Micromonospora 0rskov 

 was applied to those forms which produce 

 single spores on lateral liranches. Although 

 it was recognized that Tsiklinsky had pre- 

 \'i()usly applied the name Thermoactino- 

 myces to similar cultures, her description of 

 the genus, in which she also included thermo- 

 ])hili(' species with catenulate spores, was 

 based on temperature relations rather than 

 on morphology. 



On the l)asis of these and other considera- 

 tions, Waksman and Henrici proposed a 

 system of nomenclatvu'c and classification of 

 the Actinomycetales which has been used as 



